Several activities important for the design, data management, and implementation of the intramural controlled trials (Z01 CN 00103-03 CPSB and Z01 CN 00100-03 CPSB) have been undertaken during this fiscal year. In addition, broader research in controlled clinical trials has been conducted. Descriptions follow. The Surveillance and Operations Research Branch functions as the Data Coordinating Center for the "Use of Isotretinoin in the Prevention of Basla Cell Carcinoma" chemoprevention trial (Z01 CN00103-03 CPSB). Responsibilities include all of the usual ones for a data coordinating center as well as preparation and administration of a training program for both the clinical study coordinators and the principal investigators, and collaboration in the interim and final analyses of study data. A model for training clinic personnel in on-site study administration and patient management was developed which assures standardized study operations according to protocol requirements and allows objective assessment of study coordinator skills. A prototype system using microcomputers for distributed data collection and limited processing was developed for a multi-institutional feasibility intervention trial among high risk occupational cohorts. The use of distributed microcomputers to support chemoprevention trials and community progress was initiated. Pilot studies are a major component of large intervention trials, since the feasibility of many parameters needs to be tested before launching into a study with 2,000 or 20,000 patients. The "U.S.-Finland Beta-carotene, Alpha-tocopherol/Lung Cancer Prevention Trial" pilot study, completed in FY 1984 in collaboration with the Prevention Program, demonstrates some of these parameters.